Watch: Djokovic upset by Karatsev in Belgrade semi-finals

World number one Novak Djokovic suffered a second surprise loss in as many weeks Saturday as he was knocked out by Russia’s Aslan Karatsev in the Belgrade semi-finals.

The 28th-ranked Karatsev saved 23 of 28 break points to advance to his second final of the year following a 7-5, 4-6, 6-4 victory, gaining a measure of revenge for his defeat by Djokovic in the last four of the Australian Open.

Djokovic was also beaten in the last 16 of the Monte Carlo Masters last week by Britain’s Dan Evans.

Djokovic, the 2009 and 2011 champion at the event which is played at a venue which carries his name, surrendered a 3-0 advantage in the opening set as he dropped serve three times.

The Serb then fell 4-2 behind in the second but summoned his well-documented powers of recovery to win four straight games and send the match to a deciding set.

Dubai champion Karatsev fended off eight break points in the third set before winning Djokovic’s service game to move 4-3 ahead and leave the top seed on the brink.

Djokovic saved a match point down 5-3 to force Karatsev to serve it out. The third seed saved two further break points as he completed the biggest win of his career after three hours and 25 minutes.

Karatsev will face 10th-ranked Matteo Berrettini or Japan’s world number 126 Taro Daniel in Sunday’s final.